What was found
AIRCRAFT RETURN TO GATE, PER CREW, AFTER NORMAL LEFT ENGINE STARTED AND STARTED RIGHT ENGINE. CREW NOTICE LEFT GENERATOR TRIPPED AND SAW THAT LEFT ENGINE AUTO-SHUT DOWN BY ITSELF. CHECKED EPCS PAGE, NO FAULTS DISPLAYED. NO FAULTS FOUND ON EICAS. NO ENGINE EXCEEDANCE FAULTS. CREW NO UNUSUAL ENGINE PARAMETERS. DRY MOTORED ENGINE PER JRH 2-5-9 ALL INDICATIONS NORMAL. RAN ENGINE PER JRH 2-5-1. RAN FOR APPROX 5 MINS WITH BLD AND PACKS ON, GENERATOR PWR'G ACFT. ALL NORMAL NO FAULTS.